1. O
ne lunchtime in early March, tables
at Nairobi’s K’Osewe restaurant are
packed.Thewaitingstaffrunbackand
forth from the kitchen, bringing out steaming
platesofdeep-greenAfricannightshade,vibrant
amaranth stew and the sautéed leaves of cow-
peas. The restaurant is known as the best place
tocomeforahelpingofKenya’straditionalleafy
green vegetables, which are increasingly show-
ing up on menus across the city.
Just a few years ago, many of those plates
would have been filled with staples such as
collard greens or kale — which were intro-
duced to Africa from Europe a little over a
century ago. In Nairobi, indigenous vegetables
were once sold almost exclusively at hard-to-
find specialized markets; and although these
plants have been favoured by some rural pop-
ulations in Africa, they were largely ignored
by seed companies and researchers, so they
lagged behind commercial crops in terms of
productivity and sometimes quality.
Now, indigenous vegetables are in vogue.
They fill shelves at large supermarkets even
in Nairobi, and seed companies are breeding
more of the traditional varieties every year.
Kenyan farmers increased the area planted
with such greens by 25% between 2011 and
2013. As people throughout East Africa have
recognized the vegetables’ benefits, demand
for the crops has boomed.
This is welcome news for agricultural
researchers and nutritional experts, who argue
that indigenous vegetables have a host of desir-
able traits: many of them are richer in protein,
vitamins, iron and other nutrients than pop-
ular non-native crops such as kale, and they
are better able to endure droughts and pests.
This makes the traditional varieties a potent
weaponagainstdietarydeficiencies.“InAfrica,
malnutrition is such a problem. We want to see
indigenous vegetables play a role,” says Mary
Abukutsa-Onyango, a horticultural researcher
at Jomo Kenyatta University of Agriculture
and Technology in Juja, Kenya, who is a major
proponent of the crops.
Scientists in Africa and elsewhere are now
ramping up studies of indigenous vegetables
to tap their health benefits and improve them
through breeding experiments. The hope is
that such efforts can make traditional varieties
even more popular with farmers and consum-
ers. But that carries its own risk: as indigenous
vegetablesbecomemorewidespread,research-
ersseekingfaster-growingcropsmayinadvert-
ently breed out disease resistance or some of
the other beneficial
traits that made these
plants so desirable in
the first place.
“It is important
BY RACHEL CERNANSKY
Super vegetables
LongoverlookedinpartsofAfrica,indigenousgreensarenowcapturing
attentionfortheirnutritionalandenvironmentalbenefits.
Women sell African
nightshade and other
green vegetables at a
market in Nairobi.
1 4 6 | N A T U R E | V O L 5 2 2 | 1 1 J U N E 2 0 1 5
© 2015 Macmillan Publishers Limited. All rights reserved

2. that when we promote a specific crop, that we
try to come up with different varieties,” says
Andreas Ebert, gene-bank manager at the
World Vegetable Center (AVRDC), an agricul-
tural-research organization based in Shanhua,
Taiwan. If the increasing popularity of these
vegetables limits choices, he says, “the major
benefits we are currently seeing will be lost”.
PROTEIN FROM PLANTS
For Abukutsa, indigenous vegetables bring
back memories of her childhood. Cow’s milk,
eggs and some fish made her ill, so doctors
advisedhertoavoidallanimalprotein.Instead,
the women in her family made tasty dishes out
of the green vegetables that grew like weeds
around her house. Her mother often cooked
the teardrop-shaped leaves of African night-
shade (Solanum scabrum), as well as dishes of
slimy jute mallow (Corchorus olitorius) and
the greens of cowpeas, known elsewhere as
black-eyed peas (Vigna unguiculata). One
grandmother always cooked pumpkin leaves
(Cucurbita moschata) with peanut or sesame
paste. Abukutsa relished them all and ate the
greens with ugali, a polenta-like dish common
in East Africa.
She chose to pursue a career in agriculture
because she wanted to “unravel the potential
hidden in African indigenous vegetables”, she
says. Now, she is considered a leader across
Africa, and increasingly around the world, in a
robust, rapidly growing field. “She’s almost like
the mother of indigenous vegetables in Kenya,”
says Jane Ambuko, head of horticulture at the
University of Nairobi.
Abukutsa started out in the early 1990s,
surveying and collecting Kenya’s indigenous
plants to investigate the viability of the seeds
that farmers were using. In the decades since,
shehascometofocusmainlyonthevegetables’
nutritional properties.
Today, she is far from alone. The AVRDC
has a dedicated research and breeding pro-
gramme at its office in Arusha, Tanzania, and
theKenyaAgriculturalandLivestockResearch
Organization in Nairobi does similar work.
Other health and agriculture organizations
in both East and West Africa focus on boost-
ing consumer use and improving the viability
and yield of these crops. That fits into a global
trend emphasizing bioregional foods — using
crops that are well adapted for a given climate
and environment, rather than foreign plants
that tend to be less nutritious and require extra
water or fertilizers.
Most of the indigenous vegetables being
studied in East Africa are leafy greens, almost
all deep green in colour and often fairly bitter.
Kenyans especially love African nightshade
and amaranth leaves (Amaranthus sp.). Spider
plant (Cleome gynandra), one of Abukutsa’s
favourites for its sour taste, grows wild in East
Africa as well as South Asia. Jute mallow has a
texture that people love or hate. It turns slimy
when cooked — much like okra. Ebert says
that moringa (Moringa oleifera) is not only one
of the most healthful of the indigenous veg-
etables — both nutritionally and medicinally
— but it is also common in many countries
around the world.
Research by Abukutsa and others shows
that amaranth greens, spider plant and African
nightshade pack substantial amounts of pro-
tein and iron — in many cases, more than kale
and cabbage1
. These vegetables are generally
rich in calcium and folate as well as vitamins
A, C and E (ref. 2).
In recent years, Abukutsa has been studying
howtomaximizenutritionalbenefitsusingdif-
ferent cooking methods. Compared with raw
vegetables, boiled and fried greens contain
muchmoreusableiron3
andcouldhelptocom-
bat the high rates of anaemia in parts of East
Africa. They can also be important sources of
protein,shesays.“Somepeoplejustliveonveg-
etables, and they cannot maybe afford meat.”
Abukutsa is currently studying the anti­
oxidant activity of indigenous vegetables, as
well as how resilient they are to the effects of
climate change. Most of the traditional vari-
eties are ready for harvest much faster than
non-native crops, so they could be promis-
ing options if the rainy seasons become more
erratic — one of the predicted outcomes of
global warming. Slenderleaf (Crotolaria sp.)
is particularly hardy during drought because
it quickly establishes its taproot. “If we have
a short rain because of climate change, it can
survive,” she says. She is working with other
research partners to select vegetables with
increased tolerance for variations in rainfall
and temperature.
Early on, Abukutsa recognized that she
needed to do more to convince people to add
indigenous vegetables to their diets. Since
around 2000, she has led public education
campaigns and worked with restaurants and
supermarkets around Kenya to find out what
they would need to start
selling these foods. A
simple but significant
problem was that peo-
ple did not know how
to cook the vegetables.
Unlike larger leafy vegetables such as kale,
many of the indigenous varieties have small
leaves that must be separated from their stems
individually before cooking — a laborious
process. Recipes are often vegetable-specific;
spider plant can be cooked with sour milk, for
example,butcowpealeavesgobetterwithsoya
bean or peanut paste. Although older genera-
tions and some rural populations know what
to do with nearly any local vegetable, much of
theregion’straditionalcookingknowledgehas
been lost. So Abukutsa got to work on collect-
ingandtestingrecipestomaximizetheamount
of iron and other nutrients the dishes contain.
K’Osewewasoneofthefirstrestaurantstotake
an active interest, and others soon followed.
For Abukutsa, indigenous vegetables are not
just a research subject — they remain a central
part of her own diet. “Today at lunchtime, I
ate pumpkin leaves and nightshade,” she says.
The vegetables’ new-found popularity
is spreading throughout East Africa. At a
bustling market in Arusha, a young woman
wearing a light-blue headscarf shops for
sweet-potato leaves (Ipomoea batatas), known
locally as matembele, which have a reputation
for improving the blood. She buys them from
an elderly woman who sells almost exclu-
sively indigenous vegetables under a large red
umbrella that protects her stock from the after-
noonsun.Shesayshersalesofsuchplantshave
climbed substantially over the past five years.
GLOBAL APPEAL
Green vegetables are not the only indigenous
crops attracting researchers’ attention. In the
1990s, the US National Research Council
(NRC) in Washington DC convened a panel
to examine the potential of Africa’s ‘lost crops’,
includinggrains,fruitsandvegetables.Chaired
by renowned agricultural researcher Norman
Borlaug,thepanelconcludedthatnativeplants
held tremendous potential for improving food
security and nutritional intake across Africa,
and should be a greater focus for researchers4
.
Today, the World Agroforestry Centre in Nai-
robi is studying a range of Africa’s more than
3,000indigenousfruitspecies,andfindingthat
they are generally more nutritious, drought-
tolerant and pest- and disease-resistant than
their exotic counterparts.
But vegetables have gained the most notice,
both in the marketplace and among research-
ers. Raymond Vodouhe, a plant breeder and
geneticist with Bioversity International in
Cotonou, Benin, says that his team’s work in
WestAfricahasfocusedondomesticatingwild
vegetables. The hardy wild plants help African
families to get through periods of drought or
cropfailure,butarethreatenedbydeforestation
and other types of land-clearing. By domesti-
cating them, researchers can give farmers
more-reliable access to indigenous vegetables
so that they can better endure lean times.
The AVRDC is doing active research on
native species in Asia and Oceania, as well
PETEMULLER/PRIMEFORNATURE
Researchers
risk eliminating
the traits that
make indigenous
vegetables so
desirable in the
first place.
NATURE.COM
Toseesomeof
Africa’ssuper
greens,visit:
go.nature.com/fh7496
1 1 J U N E 2 0 1 5 | V O L 5 2 2 | N A T U R E | 1 4 7
FEATURE NEWS
© 2015 Macmillan Publishers Limited. All rights reserved

3. INFOCUSNEWS
as Africa. “A rich diversity of indigenous
vegetable species exists throughout these
areas,” says Ebert, pointing to okra and African
eggplant (Solanum aethiopicum) in Mali, bit-
ter gourd (Momordica charantia) and Malabar
spinach (Basella alba) in India, and slippery
cabbage (Abelmoschus manihot) in the Pacific
Islands. “The challenge we face is selecting
which indigenous vegetable species to study
— with more than 2,000 plants that can be
considered and consumed as vegetables, and
verylimitedresearchfunds,it’satoughchoice.”
Lessthan10%oftheAVRDC’sroughlyUS$20-
million annual budget goes to studying indig-
enous vegetables, he says.
A main focus has been basic problems such
as difficulties with germination and a lack of
information about how best to store seeds.
Indigenous vegetables are not up to modern
farming standards for characteristics such as
uniformity of seeds and yield, so there is a lot
of catching up to do.
Buteffortstoimproveindigenousvegetables
could come at a cost, say researchers. If breed-
ers focus only on increasing yields, they could
accidentally eliminate nutritional benefits.
And if farmers seek to drive up production
through monocrop agriculture — planting
just one crop — they risk losing some of the
qualities that make these vegetables such a
draw. Plots with single crops, for example, face
higher risks of being completely wiped out by
insects or diseases.
At the AVRDC’s office in Arusha in late
February, vegetable breeder Fekadu Dinssa
walks through a screened enclosure filled with
plants used for breeding. He surveys a table
covered with starter trays of little amaranth
plants from 57 breeding lines. In one tray, the
plants are twice as tall as their neighbours, but
their pale colour will not be popular in the
market, he says. Dinssa wants to breed the
fast-growing trait into other lines to develop a
new type of commercially viable amaranth. It
is a trial-and-error process that can take years.
STRENGTH IN DIVERSITY
As indigenous vegetables are planted in greater
numbers, it will be a challenge to prevent less-
common varieties from disappearing, say
researchers. That could threaten the crops’
resilience, because different varieties can carry
separate genes for resistance to pathogens and
pests. Loss of diversity could also limit the veg-
etables’ appeal. In Kenya, for example, coastal
communities tend to like giant African night-
shade, whereas western communities prefer
a variety with smaller leaves that has a much
more bitter taste.
Some narrowing of choices has already
happened. Simlaw Seeds in Nairobi, a divi-
sion of Kenya Seed Company, sells only a cou-
ple of varieties each of amaranth and African
nightshade, chosen because they are the most
popular at the national level. “Of course it’s
a concern, because practically speaking, we
can’t promote them all,” says Abukutsa. She
and other researchers compromise by pro-
moting certain types while trying to preserve
the full diversity in gene banks in Kenya and
at the AVRDC. The researchers also encourage
communities to continue growing the varieties
they have traditionally favoured.
Calestous Juma, director of the Science,
Technology, and Globalization Project at Har-
vard University in Cambridge, Massachusetts,
seestheseeffortsascrucial.Andwithadvances
in genomics, he says, researchers should seek
waystoimproveindigenouscrops—bylength-
ening their shelf life, for example — and to use
theminbreedingotherplants.“Theymayhave
traits that may be useful for other crops.”
Juma, who served on the NRC’s lost-crops
panel, urges more agricultural research centres
in Africa to study these vegetables. The work
that Abukutsa and her colleagues are doing,
he says, “should be done at every university”.
On a hot Wednesday morning in March,
Abukutsa walks around the university campus
to survey some of her students’ work. One has
spread amaranth leaves in a wooden box in the
sunlight to test how drying will alter the plants’
nutritional profile. Abukutsa stops to talk to
another student standing amid dozens of rows
ofrecentlysproutedAfricannightshadeplants,
part of an experiment on their genetic diver-
sity. “We’ve come so far,” Abukutsa says, “but
there’s still so much to be done.” ■
Rachel Cernansky is a freelance writer in
Denver, Colorado.
1. Abukutsa, M. O. O. African Indigenous Vegetables in
Kenya: Strategic Repositioning in the Horticultural
Sector (JKUAT, 2010).
2. Yang, R.-Y. & Keding, G. B. in African Indigenous
Vegetables in Urban Agriculture (eds Shackleton,
C. M., Pasquini, M. W. & Drescher, A. W.) Ch. 4
(Earthscan, 2009).
3. Habwe, F. O., Walingo, M. K., Abukutsa-
Onyango, M. O. & Oluoch, M. O. Afr. J. Food Sci. 3,
393–397 (2009).
4. NRC. Lost Crops of Africa: Volume II: Vegetables
(National Academies Press, 2006).
Nightshade and other indigenous vegetables helped to sustain Mary Abukutsa-Onyango when she was a child. She went on to pioneer research in these crops.
PETEMULLER/PRIMEFORNATURE
1 4 8 | N A T U R E | V O L 5 2 2 | 1 1 J U N E 2 0 1 5
© 2015 Macmillan Publishers Limited. All rights reserved